Cutting the dose of Prezista (darunavir) in half is not associated with any significant change in the likelihood of treatment succeeding when the antiretroviral is boosted with Norvir (ritonavir), aidsmap reports.

Norvir-boosted Prezista is not commonly used in South Africa because of its high cost. Therefore, researchers in that nation conducted a study in which they cut Prezista’s typical dose of 800 milligrams to 400 mg in hopes that the drug would work just as well at a lower dose and save money.

Findings were presented at the International AIDS Conference in Amsterdam (AIDS 2018).

The investigators recruited 300 people receiving care for HIV in Johannesburg who had been taking Kaletra (lopinavir/ritonavir) for at least six months, had taken no other protease inhibitor previously and had a fully suppressed viral load for at least two months.

The participants were randomized to stay on Kaletra or to switch to Norvir-boosted Prezista. All participants took these protease inhibitors with two additional nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs).

A total of 95 percent of those who took Norvir-boosted Prezista and 96 percent of those who stayed on Kaletra remained in the study through its 48-week mark. Of those who completed all that follow-up time, a respective 95 percent and 93 percent of each treatment group had a fully suppressed viral load after 48 weeks of treatment. Consequently, the study authors concluded that low-dose Prezista plus Norvir is noninferior to, or as effective as, Kaletra.

When the study authors included all the study participants, not just those who included follow-up, the viral suppression rates remained comparable between the two study groups.

One person taking Norvir-boosted Prezista as well as three of those who took Kaletra developed mutations in their HIV that are associated with resistance to NRTIs.

One percent of the members of each group stopped treatment because of side effects.

To read the aidsmap article, click here.

To read the conference abstract, click here.

To download the conference presentation slides, click here.


To view a webcast of the conference presentation, click here.